vndb.org/v17035This game has you play as a magical girl soldier type character and if you lose to the final boss, he brainwashes you and your rival into becoming his slaves. If you lose to every monster in the game once, THEN beat the final boss, you get corrupted into being his slave. In the sequel, there's a boss that will brainwash your character, giving them false memories making you fall in love with them. In the third game, if you lose to t he final boss again, you get a sequence that mirrors the one in the 1st game. Also hypnosis aside, the games just have really hot game over scenes. The game has no translation but is extremely simple and easy to playthrough, and if you're a hypno fetishist you can understand the nuance of a brainwashing scene even if you don't understand the language itself.
vndb.org/v18930In this game you play as a guy who has what I can only describe as a Rape Persona, with which you invade multiple girls' mind palaces breaking down their mental defenses and making them more suggestible. The game is also not translated and requires a lot of effort to actually play and complete but can be learned with enough effort.
vndb.org/v19831This game has a LOT of hypnosis content, despite not being based around it. You can undergo hypnosis therapy wherein your character is slowly broken down by a secretly evil priest, or if that's too slow for you, you can progress the story and actually fight them along with a cute priestess type character and if you lose, results in one of my favorite hentai scenes in all the games I've played. The main game is fully translated in english, but most of the DLC stuff aren't because the original creator of the game is working on an english translation of their own.
vndb.org/r56243vndb.org/r61862Both these games actually have western developers, which means it's fully in english, and also the first eroge I've played with full english voice acting. The games have you play as a bad guy type character and depending on how hard you beat the heroines down you can use mind control powers to dominate them. In the second game you can actually have the heroine dominate you instead.
Download links for these games can be found on sukebei.nyaa.si, though I strongly recommend supporting the developers instead, especially for the last two games.